The online base maps include Imagery, World Street Map and World Topographic Map. These are included by default. You can add or remove these layers from the map.
Use my favorite layer to add any layer to the Maps menu and turning off and on. You can add .lyr files to C:\My Output Data\ArcGIS Online Maps. Newly saved map services or layers must be saved to C:\My Output Data\ArcGIS Online Maps as well. The default Maps layers are installed to C:\arcgis\Business Analyst\US\Datasets\ArcGIS Online Maps.
Use Add Data from ArcGIS Online to search for other data services and layers and include them in the Maps menu for convenience. Be sure you are connected to the Internet to use the Maps menu.
A similar way to add services is through the Add Data command in ArcGIS.Feedback on this topic?